When to Plant Mizuna in Duval County, FL
May in the garden — Duval County, Florida
Welcome to May in Zone 9b. These are the moves that will have the biggest impact on your growing season.
Mizuna is a mild-flavored Japanese mustard green with feathery, deeply serrated leaves. It is fast-growing and makes an excellent addition to salads and stir-fries.
Duval County, Florida is in USDA Zone 9b. The average last spring frost is February 24 and the first fall frost is November 29, giving you a growing season of approximately 278 days.
At an elevation of 337 feet, Duval County receives approximately 56.9 inches of rainfall annually with predominantly sand soil. Summer highs average 102°F, so Mizuna may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Mizuna will need more frequent watering and organic matter to retain nutrients. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Mizuna root diseases.
Duval County Soil Profile
Soil Type
Sand
Soil pH
5-5.8
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Duval County
How your county's soil matches Mizuna's growing requirements.
Soil pH
Your soil pH (5.0–5.8) is more acidic than Mizuna prefers (6.0–7.5). Add garden lime to raise pH.
Soil Texture
Sandy soil in Duval County warms quickly in spring but drains fast. Mizuna will need more frequent watering and regular compost additions to retain nutrients.
Organic Matter
Organic matter is low (1.4%). Add 2-3 inches of compost before planting Mizuna.
How to Plant Mizuna
Fall planting: Sow 8 weeks before your first frost date for a fall harvest.
Succession Planting Mizuna
Sow every 3.4 weeks. Last sowing by Oct 15 to harvest before frost.
For a dedicated fall crop, sow by Oct 04.
Plant Water Budget
Monthly Watering Guide for Mizuna
Mizuna needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Mizuna Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 2.6" | 0" | ❄️ Dormant |
| Feb | 4.3" | 2.8" | 1.5" | 💧 Light watering |
| Mar | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Apr | 4.3" | 3" | 1.3" | 💧 Light watering |
| May | 4.3" | 3.5" | 0.8" | 💧 Light watering |
| Jun | 4.3" | 8.7" | 0" | ✅ Rainfall sufficient |
| Jul | 4.3" | 7.8" | 0" | ✅ Rainfall sufficient |
| Aug | 4.3" | 8.9" | 0" | ✅ Rainfall sufficient |
| Sep | 4.3" | 6.3" | 0" | ✅ Rainfall sufficient |
| Oct | 4.3" | 4.7" | 0" | ✅ Rainfall sufficient |
| Nov | 4.3" | 2.6" | 1.7" | 💧 Light watering |
| Dec | — | 2.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Feb–Nov in Duval County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Mizuna Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Mizuna Planting Timeline — Duval County, FL
Mizuna Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | January 27 | Jan 27 – Feb 10 |
| Transplant Outdoors | February 24 | Feb 24 – Mar 10 |
| Direct Sow | February 3 | Feb 3 – Feb 24 |
| Harvest | March 31 | Mar 31 – Apr 28 |
| Fall Sowing | October 4 | Oct 4 – Oct 18 |
Plant 0.5" deep · 6" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | Start Indoors |
| February | Start Indoors Transplant Outdoors Direct Sow |
| March | Transplant Outdoors Harvest |
| April | Harvest |
| May | — |
| June | — |
| July | — |
| August | — |
| September | — |
| October | Fall Sowing |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Only during dry spells
📅 Days to Maturity
30–45 days
🧪 Soil pH
Needs 6–7.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 9b
📆 Growing Season
278 days in Duval County
Growing Tips for Mizuna in Duval County
Direct sow Mizuna outdoors after February 24 in Duval County when soil has warmed and frost danger has passed.
Sandy soil in Duval County dries quickly — mulch Mizuna with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.
With summer highs reaching 102°F in Duval County, provide afternoon shade for Mizuna and water deeply in the morning.
Your generous 279.0-day season in Duval County allows multiple plantings of Mizuna. Sow every 15.0 days for continuous harvest.
Common pests for Mizuna in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Direct sow in spring or fall. Harvest outer leaves as needed for a cut-and-come-again approach. Mizuna is one of the most cold-tolerant Asian greens.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Mizuna in Other Locations
Frequently Asked Questions
When should I plant Mizuna in Duval County, FL?
Duval County is in Zone 9b with an average last frost of February 24. Plan your Mizuna planting based on this frost date — see the calendar above for exact timing.
What planting zone is Duval County, FL?
Duval County, Florida is in USDA Hardiness Zone 9b. The average last spring frost is February 24 and first fall frost is November 29.
Your Duval County Garden Planner — Free
A 24-page printable planner built for Duval County (Zone 9b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.